refactor: simplify how url generation works

The URLS file is no longer necessary as urls are now generated directly from the app VHOST file.

This also moves all the url generation logic to the domains plugin.

plugins/certs/certs-exists

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+source "$PLUGIN_AVAILABLE_PATH/certs/functions"
+set -eo pipefail
+[[ $DOKKU_TRACE ]] && set -x
+
+trigger-certs-certs-exists() {
+  declare desc="checks if certs exist"
+  declare trigger="certs-exists"
+  declare APP="$1"
+
+  if is_ssl_enabled "$APP"; then
+    echo "true"
+  else
+    echo "false"
+  fi
+}
+
+trigger-certs-certs-exists "$@"